Your attitude may apply to some situations, but in general preliminary judgements kill innovation. Next time after reading your comment, someone somewhere may remain silent without showing off their art, and the world will be missing the next Copernicus, Gauss, Wozniak, Stroustrup.
If I have to choose between "polite" and "innovation", I choose "innovation" any time of day. This is the same kind of difference as to "diss" someone for no real reason as opposed to letting someone just be and "blossom" so they could share their enlightenment with everyone, and thus benefit us all.